Oncogenic rearrangements of the ret proto-oncogene in thyroid tumors induced after exposure to ionizing radiation.
A high frequency (approximately 60%) of ret rearrangements in Chernobyl papillary thyroid carcinomas (PTC) has been reported recently. The data suggested that the radiation exposure may be a direct inducer of activating rearrangements in the ret gene. In our study, we have analyzed for the presence of RET/PTC oncogenes using the RT-PCR, XL-PCR, Southern blot and direct sequencing techniques, 39 human thyroid tumors from patients who had received external radiation for benign or malignant conditions. As controls, we studied 39 'spontaneous' tumors. Our results indicate that: 1) the overall frequency of ret rearrangements was 84% in papillary carcinomas (16/19) and 45% (9/20) in follicular adenomas; 2) in contrast with the results obtained in the Chernobyl tumors, the most frequently observed chimeric gene was RET/PTC1; and 3) all the tumors were negative for RET/PTC2. In the 'spontaneous' tumors, only the papillary carcinomas presented a ret rearrangement (15%: 3/20). Our data confirm the crucial role played by the ret proto-oncogene activating rearrangements in the development of radiation-associated thyroid tumors, and show, for the first time, the presence of RET/PTC genes in follicular adenomas appeared after external irradiation.
Bounacer
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Laboratoire de Génétique Moléculaire (UPR 42), Institut de Recherches sur le Cancer, CNRS IFC 1, Villejuif, France.
Wicker
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R
Schlumberger
M
M
Sarasin
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A
Suárez
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HG
D000236:Adenoma / Q000235:genetics; D002291:Carcinoma, Papillary / Q000235:genetics; D029721:Drosophila Proteins; D006801:Humans; D009381:Neoplasms, Radiation-Induced / Q000235:genetics*; D015513:Oncogene Proteins / Q000235:genetics; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D011505:Protein-Tyrosine Kinases; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000528:radiation effects*; D051096:Proto-Oncogene Proteins c-ret; D011839:Radiation, Ionizing; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000528:radiation effects*; D013964:Thyroid Neoplasms / Q000209:etiology / Q000235:genetics*
D029721:Drosophila Proteins; C000715470:MAS1 protein, human; D015513:Oncogene Proteins; D015514:Oncogene Proteins, Fusion; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila; C093573:ret-PTC fusion oncoproteins, human